Deformable roof flashing material and a method for the manufacture of a flashing rail with a skirt made from the roof flashing material

ABSTRACT

A deformable roof flashing material for use in connection with skylight windows and roof penetrating structures is provided. The roof flashing material includes a sandwich construction with two outer layers of metal foil and at least one intermediate layer positioned between the outer layers. The material has, in at least one direction, a continuous wave form. At least the intermediate layers adjacent to the outside layers are made from a non-adhesive resilient material. The wave form is formed in such a manner that it maintains the mutual positioning between the outer layers and the adjacent intermediate layers by friction.

The invention relates to a deformable roof flashing material for use inconnection with skylight windows and the like roof penetratingstructures, said roof flashing material comprising a sandwichconstruction with two outer layers of metal foil and at least oneintermediate non-adhesive layer positioned between the outer layers, inwhich the material at least in one direction has been given a continuouswaveform.

Such deformable flashing materials are used for providing a water andsnow tight connection between the roof penetrating building structurewhich may be a chimney, an air shaft, a skylight window or the like, andthe surrounding roofing.

Particularly in connection with corrugated roofing, such as for instancetiles, whereby, during mounting, a considerable deformation of theflashing material is required, the use of flashing materials withbuilt-in excess of material in the form of corrugations or foldings hasbeen proposed as a replacement for the previously used sheet lead, whichadmittedly has a good deformability but the use of which on the otherhand is connected with problems seen from an economic and environmentalpoint of view.

Thus, the EP Patent No. 38 222 and the international publishedspecification no. WO95/28536 disclose sandwich materials or compositematerials, in which the surplus material has been provided bycorrugation in waveform in one or two directions of the flashingmaterial.

In the first-mentioned publication, the individual layers of thestructure are kept together by means of an adhesive bitumen layer as theintermediate layer. Apart from the drawback, seen from an environmentalpoint of view, that the individual components of the flashing materialcannot be separated at the dismounting, the adhesive connection willhave a negative influence on the deformability of the material, and itwill in particular be difficult to obtain the lasting deformationnecessary for obtaining the desired water and snow tightness.

In the latter publication the mutual securing between the layers formingpart of the sandwich structure is established by a second corrugation ina direction substantially perpendicular to the first one. Even thoughthis material has excellent properties in respect of deformability, themanufacturing process is on account of the second corrugationnecessarily more costly, and simultaneously the number of intermediatelayers and/or the thickness thereof is limited.

From German Utility Model publication no. G 87 01 605.2 a furtherflashing material is known which comprises a lead layer coated withaluminium foil which in view of mutually securing the layers is pleatedand possibly provided with an edge folding. However, the pleatingentails that the adaptation to the subjacent roofing is made difficulton account of the sharp foldings of the pleating, which foldingsmoreover serve as breaking direction for cracks and tear, which on theother hand entails the risk of rain penetrating to the subjacent roofconstruction.

On this background it is the object of the invention to provide adeformable roof flashing material of the type mentioned by way ofintroduction and comprising in undeformed condition a sandwichconstruction in which the layers are not displaced relative to oneanother and which is moreover easy to handle during the mounting withoutthe risk that the layers of the sandwich constructions are displacedsubstantially relative to one another, which construction on the otherhand, however, allows a certain relative movement of the layers andwhich is moreover easy and cheap in manufacture and at the same timemeets the requirements to a sufficient surplus of material.

This object is met by a roof flashing material, which is characterizedin that at least the intermediate layer/s adjacent to the outer layersis/are made from a resilient material, and in that said waveform isformed in such a manner that it maintains the mutual positioning betweenthe outer layers and the adjacent intermediate layer/s by friction.

The special embodiment of waveform in combination with the resilientintermediate layer/layers causes an effective securing between the outerlayers and the adjacent layers without the use of adhesive agents, whichmight prevent deformation of the material during adaptation to thesurrounding roofing, and at the same time the single waveformestablishes the desired surplus of material, the simplified manufactureand the freedom of choice in respect of the number of layers and/or thethickness thereof. Furthermore, the material has the advantage that itwill be self-closing in case of cracks or ruptures.

In a preferred embodiment of the invention the waveform is made as asubstantially harmonic sine curve, an optimal mechanic friction beingobtained between the outer layers and the adjacent intermediatelayer/layers which are at the same time allowed to remain undeformedduring the working process.

Further advantageous embodiments of the invention are described in theremaining dependent claims.

The invention furthermore relates to a method for the manufacture of aflashing rail with a skirt made from the roof flashing material asstated in claim 12.

The invention will now be further described by way of example in thefollowing with reference to the schematic drawing, in which

FIG. 1 shows a perspective view of a flashing material according to theinvention,

FIG. 2 a cross sectional view at a larger scale along the line II—II ofthe flashing material in a first embodiment of the invention,

FIG. 3 a view corresponding to FIG. 2 of a second embodiment of theinvention,

FIG. 4 a skirt of the flashing material and a flashing rail, and

FIG. 5 an illustration of the connection of the skirt with the flashingrail.

The deformable roof flashing material 1 shown in the drawing comprises asandwich construction, which has been given a continuous waveform in asingle direction.

The sandwich construction comprises two outer layers 2, 3 of metal foil,each having a thickness of 0.05 to 0.5 mm and consisting of a materialsuited for roof flashing purposes, for instance aluminium, zinc orcopper which have or to which through surface treatment the desiredproperteries in respect of strength, deformability and weatherresistance have been imparted. In the embodiment shown in FIG. 2,between the outer layers, a single resilient, non-adhesive intermediatelayer 4 has been placed, said layer consisting in the embodiment shownof a rubber material, for instance EPDM rubber. However, said layer maybe made from any suitable material having a flexibility and elasticitywhich allows it to be deformed together with the outer layers during themanufacture and during the mounting itself. The surfaces of theintermediate layer 4 correspondingly have to possess frictionalproperties which in the shown, not deformed delivery condition have theeffect that the intermediate layer 4 and the outer layers 2, 3 are notdisplaced relative to each other, but on the other hand a certain mutualmovement is allowed between the layers during the adaptation of theflashing material to the subjacent roofing. The desired frictionalproperties may be established through surface treatment of the resilientmaterial. The thickness of the rubber layer lies in the range of 0.1 to3.0 mm, preferably 0.5 to 1.5 mm.

In the embodiment shown in FIG. 3 the sandwich construction is dividedinto five parts, whereas the structure described above is divided inthree parts, an additional intermediate layer of metal foil 7 beinginterposed between the two outer layers 2, 3 and two intermediate layers5, 6 adjacent to the outer layers and of resilient material. Thethickness of the two resilient intermediate layers 5, 6 lies within theabove range, whereas the thickness of the metal foil layer interposedvaries depending on the desired weight and rigidity increase of theflashing material.

As will be most clearly seen from FIGS. 2 and 3 the waveform has beenmade as a substantially harmonic sine curve. The sine curve has acorrugation degree expressed as the ratio between the length Lk of aunit of the flashing material after corrugation and the length Lu of thecorresponding unit in the starting position, which lies in the range of0.4 to 0.8, preferably 0.55 to 0.75, and which in the embodiment shownis approx. 0.72. The wave length relative to the height of the waves isexpressed by the ratio between the horizontal distance Lh from wavecrest to wave valley and the vertical distance Lv from wave crest towave valley and lies in the range of 0.8 to 1.2. By manufacturing thewaveform with these parameters in the above intervals, an optimalcombination of deformation and frictional properties is obtained, and atthe same time the desired harmonic sine curve prevents the resilientintermediate layers from being exposed to elastic or plasticdeformations during the manufacture, such that it/they is/are in acondition substantially free of stress and rests/rest passively betweenthe outer layers in the undeformed delivery condition.

The material is manufactured by positioning of one or more intermediatelayers between two separate metal foils, or between two halves of asingle metal foil folded along a folding line, as besides mentioned andexplained in Applicant's above-mentioned WO95/28536. Subsequently, thejoined material is corrugated to the desired corrugation degree and tothe desired ratio between wave length and wave height.

The flashing material can now for instance be coiled into a storage coilin view of subsequent cutting when used, or may be cut directly afterthe corrugation into finished pieces.

During the adaptation of the flashing material according to theinvention to the structure of the individual roofing, the resilientlayer/s will owing to the non-adhesive properties and the choicementioned above of a material with suitable surface friction propertiesbe able to follow the deformation of the remaining parts of the flashingmaterial, which has the effect that the adaptation itself takes placewithout problems, and at the same time a lasting deformation with tightabutment is obtained between the flashing material and the subjacentroofing.

When mounted the flashing material has moreover the advantage that incase of ruptures or cracks in the material due to careless handling itwill be self-sealing due to the fact that the resilient intermediatelayer/s will close around such a rupture or crack.

FIG. 4 shows a skirt 8 of the flashing material according to theinvention and a flashing rail 9 with which the skirt is to be connected.FIG. 5 shows the skirt 8 and the flashing rail 9 from the end duringassembly. The skirt 8 has a first side edge 10 which may be constitutedof a folding in the outer layer 2, 3, if the outer layers are made froma single metal foil folded as mentioned above. Furthermore, the skirt 8has two end edges 12, where at least the outer layers preferably arebent 180° to close the ends of the skirt. Finally, the skirt 8 has asecond side edge 11, in which the corrugations have been laid down toprovide a flat longitudinal flap 14, which locks the layers andfacilitates a subsequent folding.

The flashing rail 9 is folded for the formation of a rabbet channel 13,in which the flat flap 14 is introduced as shown in FIG. 5 with a brokenline, following which the skirt 10 is swung 180° as indicated by thearrow 15 to the position indicated by a fully drawn line. This rabbetingcorresponds to what has been described in Applicant's DK-B-151 112 andcorresponding EP-A-0 196 831, and as done according to thesepublications a resilient adhesive strip may be inserted in the joint.

According to the above an advantageous manufacturing method, in whichthe flashing material is manufactured with a view to forming partdirectly in a production of pre-manufactured flashing skirts connectedwith flashing rails, may comprise

conveyance of a web-shaped metal foil,

folding of the metal foil,

insertion of a rubber cloth in the folded metal foil,

corrugation of metal foil with rubber cloth,

flattening of the not folded side edge of the folded metal foil for theformation of a flat flap,

cutting of the metal foil web in predetermined lengths,

folding of the end edges created by the cutting for the formation of askirt with closed ends,

introduction of the flat flap in a rabbet channel in a flashing rail,preferably together with a resilient, adhesive strip of for instancebutyl rubber, and

bending of the flattened flap for securing together the skirt and theflashing rail.

What is claimed is:
 1. A deformable roof flashing material for use inconnection with skylight windows and the like roof penetratingstructures, said roof flashing material comprising a sandwichconstruction with two outer layers (2, 3) of metal foil and at least oneintermediate layer (4; 5-7) positioned between the outer layers, saidmaterial having at least in one direction a continuous waveform, whereinat least the intermediate layer/s (4; 5, 6) adjacent to the outer layersis/are made from a non-adhesive resilient material having a flexibilityand elasticity such that the intermediate layer/s is/are deformable withthe outer layers during mounting, and in that said waveform is formed insuch a manner that it maintains the mutual positioning between the outerlayers and the adjacent intermediate layer/s by friction.
 2. A roofflashing material according to claim 1, wherein said waveform is made asa substantially harmonic sine curve.
 3. A roof flashing materialaccording to claim 2, wherein the degree of corrugation expressed as theratio between the length after corrugation (Lk) and the length in thestarting condition (Lu) is in the range of 0.4 to 0.8.
 4. A roofflashing material according to claim 2, wherein the ratio between thehorizontal distance from wave crest to wave valley (Lh) and the verticaldistance from wave crest to wave valley (Lv) is within the range of 0.8to 1.2.
 5. A roof flashing material according to claim 1, wherein the atleast one intermediate layer (4) is a single resilient layer made from arubber material.
 6. A roof flashing material according to claim 5,wherein said rubber material consists of EPDM rubber.
 7. A roof flashingmaterial according to claim 5, wherein each resilient rubber layer (4;5,6) has a thickness between 0.5 and 1.5 mm.
 8. A roof flashing materialaccording to claim 5, wherein each resilient rubber layer (4; 5, 6) hasa thickness between 0.1 and 3.0 mm.
 9. A roof flashing materialaccording to claim 1, wherein the metal foil of the outer layers (2, 3)includes at least one of aluminum, zinc and copper.
 10. A roof flashingmaterial according to claim 9, wherein each outer layer (2, 3) has athickness between 0.05 and 0.5 mm.
 11. A roof flashing according toclaim 9, wherein the outer layers (2, 3) consist of parts of one and thesame piece of material which is folded along a folding line.
 12. A roofflashing material according to claim 1, wherein the at least oneintermediate layer includes two resilient intermediate layers (5, 6) ofrubber and a metal foil layer (7) interposed between these layers.
 13. Aroof flashing material according to claim 1, wherein the degree ofcorrugation expressed as a ration between the length after corrugation(Lk) and the length in the starting condition (Lu) is in the range of0.55 to 0.75.
 14. A method for the manufacture of a flashing rail with askirt made from roof flashing material comprising a sandwichconstruction with two outer layers of metal foil and at least oneintermediate non-adhesive layer positioned between the outer layers,said material having at least in one direction a continuous waveform,wherein at least the intermediate layer/s adjacent to the outer layersis made from a resilient material having a flexibility and elasticitysuch that the intermediate layer/s is/are deformable with the outerlayers during mounting, and in that said waveform is formed in such amanner that it maintains the mutual positioning between the outer layersand the adjacent intermediate layer/s by friction, comprising: conveyinga web-shaped metal foil; folding the metal foil; inserting a rubbercloth in the folded metal foil; corrugating the metal foil with rubbercloth; flattening the unfolded side edge of the folded metal foil toform a flat flap; cutting the metal foil web in predetermine lengths;folding the end edges created by the cutting to form a skirt with closedends; introducing the flat flap into a rabbet channel in a flashingrail; and bending the flattened flap to secure together the skirt andthe flashing rail.
 15. The method of claim 14, wherein the flat flap isintroduced into the rabbet channel in a flashing rail together with aresilient, adhesive strip.
 16. The method of claim 15, wherein theresilient adhesive strip is made of butyl rubber.